This calculator uses the Metabolic Equivalent of Task (MET) formula to estimate energy expenditure. Running is one of the most effective ways to burn calories because it engages multiple large muscle groups and requires significant cardiovascular effort.
The Science: The MET Formula
The standard equation used is: Total Calories = MET × Weight (kg) × Time (hours).
A MET is a unit that represents the energy cost of physical activity. Sitting quietly is 1 MET. Running has much higher MET values depending on your pace:
Slow Jog (5 mph): 8.3 METs
Moderate Run (6 mph): 9.8 METs
Steady Run (7.5 mph): 11.5 METs
Fast Run (10 mph): 14.5 METs
Factors Affecting Your Burn Rate
While this tool provides a highly accurate estimate, several factors can influence your actual results:
Body Weight: Heavier individuals burn more calories because it requires more energy to move more mass.
Pace and Intensity: Faster speeds increase your heart rate and energy demand exponentially.
Incline: Running uphill can increase calorie burn by as much as 30% to 50% compared to flat ground.
Surface: Running on sand or trail terrain requires more stabilization and effort than running on a treadmill or asphalt.
Example Calculations
Example 1: A 155 lb (70 kg) runner completes 5 miles in 45 minutes. Their speed is 6.67 mph (MET of ~10.5). They would burn approximately 550 calories.
Example 2: A 200 lb (90.7 kg) runner jogs for 30 minutes at 5 mph (MET of 8.3). They would burn roughly 376 calories.
function calculateRunningCalories() {
var weight = parseFloat(document.getElementById('runnerWeight').value);
var weightUnit = document.getElementById('weightUnit').value;
var time = parseFloat(document.getElementById('runningTime').value);
var distance = parseFloat(document.getElementById('runningDistance').value);
var distanceUnit = document.getElementById('distanceUnit').value;
if (isNaN(weight) || isNaN(time) || isNaN(distance) || weight <= 0 || time <= 0 || distance <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Convert weight to kg
var weightKg = weight;
if (weightUnit === "lbs") {
weightKg = weight * 0.453592;
}
// Convert distance to miles for speed calculation
var distanceMiles = distance;
if (distanceUnit === "km") {
distanceMiles = distance * 0.621371;
}
// Calculate Speed in mph
var timeHours = time / 60;
var speedMph = distanceMiles / timeHours;
// Determine MET based on speed (Interpolation/Steps)
var met = 0;
if (speedMph < 4) met = 6.0;
else if (speedMph < 5) met = 8.3;
else if (speedMph < 6) met = 9.8;
else if (speedMph < 7) met = 11.0;
else if (speedMph < 8) met = 11.8;
else if (speedMph < 9) met = 12.8;
else if (speedMph < 10) met = 14.5;
else if (speedMph < 11) met = 16.0;
else if (speedMph < 12) met = 19.0;
else met = 23.0;
// Formula: Cal = MET * Weight(kg) * Time(hrs)
var totalCalories = met * weightKg * timeHours;
// Calculate Pace
var paceInMinutes = time / distanceMiles;
var paceMinutes = Math.floor(paceInMinutes);
var paceSeconds = Math.round((paceInMinutes – paceMinutes) * 60);
if (paceSeconds < 10) paceSeconds = "0" + paceSeconds;
// Display Results
document.getElementById('calorieResultBox').style.display = 'block';
document.getElementById('calorieOutput').innerText = Math.round(totalCalories).toLocaleString();
document.getElementById('paceOutput').innerHTML = "Average Speed: " + speedMph.toFixed(2) + " mphAverage Pace: " + paceMinutes + ":" + paceSeconds + " min/mile";
// Smooth scroll to result
document.getElementById('calorieResultBox').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}